A general image forming apparatus having a stapler will be described with reference to FIG. 1.
As shown in FIG. 1, the image forming apparatus such as a copier 1 includes a paper finishing apparatus 2 that finishes papers ejected from the image forming apparatus. The paper finishing apparatus 2 is located at a side of the image forming apparatus, and includes an image tray module 15, a finisher module 20, and a paper conveyer module 40.
The image tray module 15 stacks papers finished through the copier 1 onto an image tray 22. The finisher module 20 punches the finished papers using a punch 25 and staples the papers using a stapler 24 so as to stack the papers onto a stack tray 27. The paper conveyer module 40 distributes the papers to the image tray module 15 and the finisher module 20.
The above modules are detachably assembled into the finishing apparatus, and other modules having various functions may additionally be provided to the paper conveyer module.
An example of a related art stapler moving guide device of the stapler 24 provided in the finisher module 20 is disclosed in the Korean Patent Publication No. 2000-28390. The related art stapler moving guide device will be described with reference to FIGS. 2 and 3.
The related art stapler moving guide device 30 positions a stapler frame 31 along the stapler 24 at an opposing position adjoining the end of papers 3. The stapler frame 31 includes a slide groove 33a having an extension extending in parallel with the end of the papers 3, and a stapler moving path 33 having first and second tilt slide grooves 33b and 33c extending from both ends of the slide groove 33a to the papers 3 by a predetermined distance with a tilt angle. The slide groove 33a and the stapler moving path 33 are provided in the stapler frame to form a single body.
First and second support shafts 34a and 34b extended below the stapler 24 are fitted into the stapler moving path 33 so that the stapler 24 is slid. A guide plate 35 fixed to the first and second support shafts 34a and 34b is provided below the stapler frame 31.
The guide plate 35 is fitted into a guide plate moving shaft 36 and is configured to move-along the moving shaft 36. The moving shaft 36 is fixed below the stapler frame 31 in parallel with the slide groove 33a. 
Belt fitting wheels 39a and 39b are fixed to both ends of the moving shaft 36. A driving belt 37 is fitted into the belt fitting wheels 39a and 39b so that it is driven in parallel with the moving shaft 36.
The driving belt 37 is driven by a motor 38 provided in the stapler frame 31, and the circumference of the driving belt 37 is fixed to a belt clamp 41 of the guide plate 35.
Once the driving belt 37 is rotated by rotation of the motor 38, the guide plate 35 connected with the driving belt 37 moves along the moving shaft 36 and the stapler 24 below which the first and second support shafts 34a and 34b are fixed to the guide plate 35 moves along the moving path 33.
Meanwhile, a first cam hole 42a and a second cam hole 42b are formed at a portion into which the first and second support shafts 34a and 34b are fitted. The first cam hole 42a is to move the first support shaft 34a and the second cam hole 42b is to move the second support shaft 34b. The first and second cam holes 42a and 42b have a symmetrical arch shape.
The first and second cam holes 42a and 42b are formed to rotate the stapler 24 along the tilt slide groove at a certain angle when the stapler 24 moves to the first tilt slide groove 33b or the second tilt slide groove 33c. 
The aforementioned related art stapler moving guide device 30 positions the stapler 24 in a horizontal direction at the center of the papers 3 while in a tilt direction at both corners of the papers, thereby enabling tilt stapling at the corners of the papers.
However, the aforementioned related art stapler moving guide device has several problems.
There is limitation in moving the paper conveyer (not shown in FIGS. 2 and 3) that moves the papers 3 to staple them to the stapler frame 31 where the stapler 24 is positioned.
In other words, to move the stapled papers 3 to stack them onto the stack tray 27, the paper conveyer that pushes the central end of the stapled papers 3 to move to the stack tray is required. Since such a paper conveyer is caught in the stapler if the stapler is positioned at the center, it cannot move to the end of the papers.
For this reason, the stapler moves from the center to the side after stapling operation and then the paper conveyer should move. In addition, since movement of the paper conveyer is determined depending on the position of the stapler, the movement of the paper conveyer may be delayed. Such delay of the movement of the paper conveyer reduces driving efficiency of the stapler moving guide device.